DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant's arguments filed March 10, 2026 have been fully considered.
The objection to the specification is withdrawn based on the amendments to the specification. The 35 U.S.C 112(b) rejections are withdrawn based on the amendments.
The applicant argues that the modification to Kasatani based on the teachings of Parker would render it unsatisfactory for its intended purpose. The applicant argues that causing the axial projection areas (Ia) and (Ib) of examiner’s Annotated Figure would change the sealing principle of how the sealing which is critical to the device of Kasatani.
First, the examiner disagrees that any exposure of (Ia) or (Ib) in Annotated Figure 1 would negatively impact the sealing of the volatile fluid making it unsatisfactory for its intended purpose. The same force provided by springs (23) and (24) to provide sealing between (22A)/(22B) and (21A)/(21B) would also be sufficient to seal the interface between (22A) and (40) as well as (21A) and (40).
The examiner also finds that the applicant narrowly interprets the exact details of the different possibilities how one of ordinary skill in the art would achieve the modification to Kasatani. For example, to achieve the modification the structure of (40) of Kasatani may extend the axial width of (22A) and (21A) near the radial location of (38). This makes it so that (40) is exposed to the gas on the axial sides. For clarity, this modification is done by the structure of (21A) and (22A) beginning at a more radially outward location than as depicted in Kasatani. The rejections are therefore maintained.
Any changes to the rejections below are necessitated by amendment; therefore the rejections are final.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-4, 8-10, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Kasatani et al. (U.S Pre-Grant Publication 20210262481) hereinafter Kasatani in view of Parker et al. (U.S Patent 5,941,531) hereinafter Parker.
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Regarding claim 1, Kasatani discloses:
An assembly for compensating axial forces in a rotating flow machine {[0051]-[0056]. It is noted that the phrase “for compensating axial forces” is considered by the examiner as an intended purpose but is not considered a structural limitation. The examiner still finds that the structure of Kasatani that corresponds to the claim limitations below would have a balancing effect even if it is not large. Additionally, Kasatani has other features of the assembly that perform balancing such as (15)/(16)}, comprising;
a housing {Figure 2 (35)};
a shaft rotatably arranged to the housing {Figure 2 (5) including (38)};
a rotationally symmetrical balancing part arranged to and coaxially with the shaft in the housing {Figure 2 (40)};
the balancing part having:
a first axial end {Figure 2 (40) has a first axial end on the left of the figure}
with a first axial face projection having a first width {Annotated Figure 1 (Ia) has a first width (W1)},
which together with a diameter of the shaft defines a first axial projection area of the first axial end {The first axial projection area is an annular shape that is defined by the first width and a hole in the center defined by the diameter of the shaft}, and
a second axial end {Figure 2 (40) has a second axial end on the right of the figure};
having a second axial face projection having a second width {Annotated Figure 1 (Ib) has a second outer radius (W2)},
which together with the diameter of the shaft defines a second axial projection area of the second axial end {The second axial projection area is an annular shape that is defined by a second width and a hole in the center defined by the diameter of the shaft}
wherein the first axial projection area and a prevailing pressure defining an axial force exerted to the first end of the balancing part
{Annotated Figure 1, The first axial projection area (Ia) and prevailing pressure defines an axial force exerted to the first end of the balancing part because an axial force is exerted on (Ia) via (22A) and (22B) from the prevailing pressure applied to areas (IIa) that are equivalent to (Ia). The concept of the pressure being defined by the axial projection area and a prevailing pressure is found not be incompatible with the indirect transfer of forces in the configuration of Kasatani. If the axial projection area of (40) is equivalent to an area that is acted upon by a pressure and the orientation (directionality) of the areas are the same, then the resulting force is identical. Therefore, it is found that the axial projection area of (40) (together with the pressure characteristics of the fluid not in direct contact) would define the axial force}
a first mechanical slide ring sealing arranged between the balancing part and the housing at the first axial end {Figure 2 (22B) is arranged between the balancing part (40) and the housing on the first axial end which is the left; [0057]};
a second mechanical slide ring sealing arranged between the balancing part and the housing at the second axial end the first {Figure 2 (21B) is arranged between the balancing part (40) and the housing on the second axial end which is the right; [0057]} and
the second mechanical slide ring sealings arranged so as to seal an intermediate space, extending axially between the mechanical slide ring sealings {Figure 2 (21B) and (22B) seal intermediate space (30), [0076]. The intermediate space may be interpreted as only part of (30)},
the intermediate space being bordered by the slide ring sealings the balancing part and the housing {Figure 2 (30) is bordered by (21A/B), (22A/B), (40), and (35)}; and
a first fluid communication port opening into the intermediate space {Figure 2 (53) is a port that communicates with (30), [0063]},
the first fluid communication port being connected to a source of pressurized barrier fluid {Figure 2 (53) is connected to a source (46) of pressure barrier fluid; [0062]-[0063]}, and
the first axial end has a first width and the second axial end has a second width, the first width being equal to the second width {Figure 2, (40) is symmetric where the widths of the first and second axial ends are equal. Annotated Figure 1 (W1) and (W2) are equal}
Kasatani does not disclose:
the prevailing pressure being caused by the first axial projection area being in contact with the fluid.
Parker pertains to sealing / balancing configurations in pumps. Parker teaches:
The prevailing pressure being caused by the first axial projection area being in contact with the fluid {Figure 2, the balancing part (32) has first and second axial projection areas that are in contact with the fluid which exerts the prevailing pressure; Column 12 lines 37-46}.
{It is noted that the claimed functionality is achieved in Parker by having the rotating-side seals of (34)/(35) and (41)/(42) only extend a portion of the radial length of (32) and does not extend all the way to (52)}
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have the prevailing pressure being caused by the axial projection area being in contact with the fluid as taught by Parker for the configuration of Kasatani. This can be achieved by having the rotating-side seal rings (21A/22A) of Kasatani not extend to the sleeve (38) but rather only part of the radial distance as taught by Parker as described above. One of ordinary skill in the art would be motivated to do so the change in configuration of the rotor-side sealing from that of Kasatani to that of Parker which leaves the rotor exposed to the fluid is a simple substitution of one known element for another to obtain predictable results. Both rotor-side sealings have known functions of providing sealing and the substitution has predictable results of the there being a sealed interaction between the rotor and the stationary seal. See MPEP 2143 I B.
Regarding claim 2, Kasatani further discloses:
a second communication port opening into the intermediate space {Figure 20 (58); [0068]}, and
a fluid circulation channel connecting the first fluid communication port and the second communication port with each other {Figure 2, a portion of (30) that is not interpreted as the intermediate space may be interpreted as connecting (53) and (58) with each other; [0068]}.
Regarding claim 3, Kasatani further discloses:
wherein the fluid circulation channel is connected to a source of pressurized fluid {Figure 2, the fluid circulation channel described above is fluidly connected to (47); [0062]}.
Regarding claim 4, Kasatani further discloses:
a second communication port opening into the intermediate space and the second fluid communication port being connected to a fluid discharge system {Figure 2, a second communication port opening which may be any cross section of (56) and the second fluid communication port (58) are connected to a fluid discharge system (57)/(61); [0068]}.
Regarding claim 8, Kasatani further discloses:
wherein the first mechanical slide ring sealing comprises a first stationary sealing ring supported to the housing in an axially movable manner {Figure 2 (21B) is a stationary sealing ring supported to the housing (35) in an axially movable manner; [0057]-[0059]},
a spring element configured to cause an axial force to the first stationary sealing ring to urge the first stationary sealing ring towards the balancing part {Figure 2 (23) causes an axial force on (21B) to urge it towards balancing part (40); [0057]}, and
the second slide ring sealing comprises a second stationary sealing ring supported to the housing in an axially movable manner {Figure 2 (22B) is a stationary sealing ring supported to the housing (35) in an axially movable manner; [0057]-[0059]},
a spring element configured to cause an axial force to the second stationary sealing ring to urge the second stationary sealing ring towards the balancing part {Figure 2 (24) causes an axial force on (22B) to urge it towards balancing part (40); [0057]}.
Regarding claim 9, Kasatani further discloses:
wherein the balancing part includes a ring member configured to cooperate with the first stationary sealing ring and the second stationary sealing ring {Figure 2 (22A/B) respectively cooperate with the first and second stationary sealing rings (21A/B); (22A/B) may be considered as part of the balancing part as (40) and (22A/B) rotate together; [0057]}.
Regarding claim 10, Kasatani further discloses:
a multi-stage centrifugal pump {Figure 1, (7); [0051]}, comprising: having
a drive shaft {Figures 1 / 2 (5)}
a plurality of impellers arranged to the drive shaft {Figure 1 (7) is connected to (5); [0052]}, and
the assembly for compensating axial forces according to claim 1 {see above}
Regarding claim 15, the combination of Kasatani and Parker further teaches:
Wherein the prevailing pressure is a first prevailing pressure defining a first axial force, and
the second axial projection area and a second prevailing pressure define a second an axial force exerted to the second end of the balancing part
{Parker Figure 2, the balancing part (32) has first and second axial projection areas that are in contact with the fluid which exerts the prevailing pressure; Column 12 lines 37-46. The modification described in claim 1 is applied to both axial sides and therefore the same explanation as described in claim 1 for the first axial projection area and first end applies to the second axial projection area and the second end}
Claims 5 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Kasatani in view of Parker as applied to claim 1 above, and in further view of Hildenbrand (WO2012079765) hereinafter Hildenbrand.
Regarding claim 5, the combination of Kasatani and Parker teaches the assembly for compensating axial forces in a rotating flow machine of claim 2, but does not teach:
wherein the circulation channel is fluidly connected to a working space of the rotating flow between an inlet and an outlet.
Hildenbrand pertains to pump configurations and also to double sealing configurations which makes it from the same field of endeavor as the claimed invention.
Hildenbrand teaches wherein the intermediate space is fluidly connected to a working space of the rotating flow between an inlet and an outlet {Figure 1 (43) is between the inlet and outlet of the rotating flow from the pump and sends the working fluid to the region of the intermediate space (9)}.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have fluidly connected the intermediate space to the working space of the rotating flow between an inlet and an outlet (using working fluid as the barrier fluid) as taught by Hildenbrand for the configuration of the combination of Kasatani and Parker. One of ordinary skill in the art would be motivated to do so as working fluid (in a certain form) may be used as a barrier fluid in the case of carbon dioxide being the working fluid {Hildenbrand [0013]}. Kasatani teaches the barrier fluid is typically an inert gas, carbon dioxide gas, or air {[0064]}.
The combination of Kasatani, Parker, and Hildenbrand therefore teaches wherein the circulation channel is fluidly connected to a working space of the rotating flow between an inlet and an outlet {The circulation channel of Kasatani is part of (30) which also forms the intermediates space, so the circulation channel of Kasatani is fluidly connected to the working space based on the modification using the teachings of Hildenbrand where the barrier fluid is the working fluid}.
Regarding claim 13, the combination of Kasatani and Parker teaches the assembly for compensating axial forces in a rotating flow machine of claim 3, but does not teach:
wherein the circulation channel is fluidly connected to a working space of the rotating flow between an inlet and an outlet.
Hildenbrand pertains to pump configurations and also to double sealing configurations which makes it from the same field of endeavor as the claimed invention.
Hildenbrand teaches wherein the intermediate space is fluidly connected to a working space of the rotating flow between an inlet and an outlet {Figure 1 (43) is between the inlet and outlet of the rotating flow from the pump and sends the working fluid to the region of the intermediate space (9)}.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have fluidly connected the intermediate space to the working space of the rotating flow between an inlet and an outlet (using working fluid as the barrier fluid) as taught by Hildenbrand for the configuration of the combination of Kasatani and Parker. One of ordinary skill in the art would be motivated to do so as working fluid (in a certain form) may be used as a barrier fluid in the case of carbon dioxide being the working fluid {Hildenbrand [0013]}. Kasatani teaches the barrier fluid is typically an inert gas, carbon dioxide gas, or air {[0064]}.
The combination of Kasatani, Parker, and Hildenbrand therefore teaches wherein the circulation channel is fluidly connected to a working space of the rotating flow between an inlet and an outlet {The circulation channel of Kasatani is part of (30) which also forms the intermediates space, so the circulation channel of Kasatani is fluidly connected to the working space based on the modification using the teachings of Hildenbrand where the barrier fluid is the working fluid}.
It is noted that the combination of Kasatani, Parker, and Hildenbrand still teaches the limitation of claim 3:
wherein the fluid circulation channel is connected to a source of pressurized fluid {the combination of Kasatani, Parker, and Hildenbrand may keep the pump (47) of Kasatani even though the fluid is coming from a pressurized source of fluid as (43) of Hildenbrand is downstream of the pump. Hildenbrand recognizes that a separate pump may still be used to have the barrier fluid at the desired pressure level, [0014]}.
Claim 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Kasatani in view of Parker as applied to claim 10 above, and in further view of Hildenbrand (WO2012079765) hereinafter Hildenbrand and Bardon et al. (U.S Pre-Grant Publication 20140225325) hereinafter Bardon.
Regarding claim 11, the combination of Kasatani and Parker teaches the assembly for compensating axial forces in a rotating flow machine of claim 10 and also:
a second communication port opening into the intermediate space {Kasatani Figure 20 (58); [0068]}, and
a fluid circulation channel connecting the first fluid communication port and the second communication port with each other {Kasatani Figure 2, a portion of (30) that is not interpreted as the intermediate space may be interpreted as connecting (53) and (58) with each other; [0068]}.
Kasatani does not teach:
wherein the circulation channel is fluidly connected to a stage of the pump between a first and a last stage of the pump.
Hildenbrand pertains to pump configurations and also to double sealing configurations which makes it from the same field of endeavor as the claimed invention.
Hildenbrand teaches wherein the intermediate space is fluidly connected to an outlet region of a compressor stage {Figure 1 (43) is between the inlet and outlet of the rotating flow from the pump and sends the working fluid to the region of the intermediate space (9)}.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have fluidly connected the intermediate space to the outlet region of a pump stage (using working fluid as the barrier fluid) as taught by Hildenbrand for the configuration of the combination of Kasatani and Parker. One of ordinary skill in the art would be motivated to do so as working fluid (in a certain form) may be used as a barrier fluid in the case of carbon dioxide being the working fluid {Hildenbrand [0013]}. Kasatani teaches the barrier fluid is typically an inert gas, carbon dioxide gas, or air {[0064]}.
The combination of Kasatani, Parker, and Hildenbrand therefore teaches wherein the circulation channel is fluidly connected to a pump stage {The circulation channel of Kasatani is part of (30) which also forms the intermediates space, so the circulation channel of Kasatani is fluidly connected to the working space based on the modification using the teachings of Hildenbrand where the barrier fluid is the working fluid}.
The combination of Kasatani, Parker, and Hildenbrand is silent as to what stage of the multi-stage pump of Kasatani would be connected to the circulation channel as Hildenbrand is only a single pump.
Bardon pertains to multi-stage pump configurations and also to sealing configurations which makes it from the same field of endeavor as the claimed invention. Bardon teaches:
The barrier fluid is delivered at a pressure of roughly 297.2kPa, the region between seals 110 and 112 is at roughly 228.2kPa, and the outlet of the final stage of the pump is at 2328.4 kPa {[0035]-[0036]}.
Since the combination of Kasatani, Parker, and Hildenbrand is silent regarding which stage of the multi-stage pump of Kasatani would be connected to the circulation channel one of ordinary skill in the art would have to choose. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have chosen a pumping stage in between the first and last stage of the pump of the combination of Kasatani, Parker and Hildenbrand to be connected to the circulation channel. One of ordinary skill in the art would be motivated to do so to have the barrier fluid be at an appropriate pressure to provide the desired sealing effect (prevent leaked gas from reaching out to the atmosphere) while also not being at too high to have excessive amounts of gas leak across seals {Bardon [0035]-[0037], see also Hildenbrad [0012]-[0014], and Kasatani [0070]}.
Regarding claim 12, the combination of Kasatani and Parker teaches the assembly for compensating axial forces in a rotating flow machine of claim 10.
Kasatani does not teach:
wherein the circulation channel is fluidly connected to the centrifugal pump at a location which provides 30%-70% of a maximum pressure of the pump.
Hildenbrand pertains to pump configurations and also to double sealing configurations which makes it from the same field of endeavor as the claimed invention.
Hildenbrand teaches wherein the intermediate space is fluidly connected to an outlet region of a compressor stage {Figure 1 (43) is between the inlet and outlet of the rotating flow from the pump and sends the working fluid to the region of the intermediate space (9)}.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have fluidly connected the intermediate space to the outlet region of a pump stage (using working fluid as the barrier fluid) as taught by Hildenbrand for the configuration of the combination of Kasatani and Parker. One of ordinary skill in the art would be motivated to do so as working fluid (in a certain form) may be used as a barrier fluid in the case of carbon dioxide being the working fluid {Hildenbrand [0013]}. Kasatani teaches the barrier fluid is typically an inert gas, carbon dioxide gas, or air {[0064]}.
The combination of Kasatani, Parker, and Hildenbrand therefore teaches wherein the circulation channel is fluidly connected to a centrifugal pump stage {The circulation channel of Kasatani is part of (30) which also forms the intermediates space, so the circulation channel of Kasatani is fluidly connected to the working space based on the modification using the teachings of Hildenbrand where the barrier fluid is the working fluid}.
The combination of Kasatani, Parker, and Hildenbrand is silent as to what portion of the multi-stage centrifugal pump of Kasatani would be connected to the circulation channel as Hildenbrand is only a single stage pump.
Bardon pertains to multi-stage pump configurations and also to sealing configurations which makes it from the same field of endeavor as the claimed invention. Bardon teaches:
the barrier fluid is delivered at a pressure of roughly 297.2kPa, the region between seals 110 and 112 is at roughly 228.2kPa, and the outlet of the final stage of the pump is at 2328.4 kPa {[0035]-[0036]}.
Since the combination of Kasatani, Parker, and Hildenbrand is silent regarding which stage of the multi-stage pump of Kasatani would be connected to the circulation channel one of ordinary skill in the art would have to choose. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have chosen a pumping stage outlet with a pressure of 30% to 70% of a maximum pressure of the pump for the combination of Kasatani, Parker, and Hildenbrand to be connected to the circulation channel. One of ordinary skill in the art would be motivated to do so to have the barrier fluid be at an appropriate pressure to provide the desired sealing effect (prevent leaked gas from reaching out to the atmosphere) while also not being at too high to have excessive amounts of gas leak across seals {Bardon [0035]-[0037], see also Hildenbrand [0012]-[0014], and Kasatani [0070]}. The pressure of the barrier fluid is a result effective variable as evidenced by the portions of the prior art directly above. It therefore would have been obvious to one of ordinary skill in the art to use routine optimization to have used a source of the barrier fluid at the claimed pressure relative to the maximum pressure of the multi-stage pump, see MPEP 2144.05 II. It is also noted that one of ordinary skill in the art has to do the basic design of the details of the multi-stage pump including the geometry of the impellers, number of stages, and design of the other seals. The different designs of these elements will result in different numerical relationships of the relevant pressures than the values discussed in Bardon.
Allowable Subject Matter
Claims 6 and 7 are allowed.
The following is an examiner’s statement of reasons for allowance:
The reasons for allowance are the same as discussed on page 16 and 17 of the office action of July 31, 2025.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL K. REITZ whose telephone number is (571)272-1387. The examiner can normally be reached M-F 7:30 a.m. -5:30 p.m.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Courtney Heinle can be reached at 5712703508. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/MICHAEL K. REITZ/Examiner, Art Unit 3745
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